Sun Coast Cycle Sports carries inspected used parts for the 2017-2019 Harley-Davidson FLHX Street Glide and FLHXS Street Glide Special equipped with the Milwaukee-Eight 107 engine (1746cc). The M8 transformed the Street Glide with four-valve heads, a single-cam valvetrain, and significantly improved Showa SDBV front suspension. Our Florida technicians disassemble donor FLHX motorcycles, evaluate each component, photograph it under a unique SKU, and ship free throughout the continental United States. Starting in 2019, many Street Glide Special models received the M8 114 engine, so confirm displacement when ordering engine-specific parts.
FLHX Street Glide 107ci generation and parts compatibility
The M8 107 Street Glide covers 2017-2019 for most variants, though the displacement transition to 114ci began during this window.
| Year | FLHX (base) | FLHXS (Special) | Key Changes |
|---|
| 2017 | M8 107 | M8 107 | First year M8, Showa SDBV fork, new exhaust routing, updated rear shocks |
| 2018 | M8 107 | M8 107 | Special gets blacked-out treatment, extended saddlebag lowers |
| 2019 | M8 107 | M8 114 (upgraded) | Special bumped to 114ci; Boom! Box GTS with Apple CarPlay on Special |
The 2019 model year is critical for parts ordering: the base FLHX retained the M8 107, but the FLHXS Special was upgraded to the M8 114 (1868cc). The two engines share crankcase architecture and most external covers, but cylinders, pistons, and ECM calibration are displacement-specific. Always verify the actual engine displacement on any 2019 Street Glide before ordering internal engine components.
The Street Glide's 19-inch Enforcer front wheel, lowered rear air suspension, and custom bagger profile carried over from the TC103 Rushmore era. Many bodywork items (saddlebags, fenders, fairing shells, seats) from 2014-2016 TC103 Rushmore Street Glides may physically fit the 2017+ M8 models, as the frame dimensions are shared. Engine, exhaust, air cleaner, and primary drive are M8-specific and incompatible with TC103.
The Boom! Box infotainment system evolved during this period. The 2017-2018 models used the Boom! Box 6.5GT (on Special) or 4.3 (on base). For 2019, the Special received the Boom! Box GTS with Apple CarPlay integration, a feature that cannot be retroactively added to earlier head units via software update.
Common FLHX Street Glide 107ci failure points and replacement parts
Exhaust header gasket ticking: The M8's exhaust header gaskets can develop leaks, creating a rhythmic ticking that varies with temperature. This is most noticeable on cold starts and typically worsens over time. The M8 header gaskets are a different design from the TC103 and are not interchangeable.
Rear shock air seal degradation (lowered suspension): The Street Glide's factory-lowered rear air shocks remain susceptible to seal wear, particularly in warm climates. A sagging rear end and bottoming over bumps indicate failed shock seals. The M8-era shocks use the same emulsion technology introduced in 2017 but with updated valving compared to the TC103 era.
Boom! Box GTS software issues (2019 Special): The 2019 Boom! Box GTS with Apple CarPlay introduced new connectivity features but also new software bugs, including CarPlay disconnection during rides, Bluetooth audio dropouts when switching between phone and navigation, and touchscreen lag in direct sunlight.
Clutch drag in cold weather: Some M8 Touring owners report clutch drag (difficulty shifting into first or neutral) when the engine is cold. This is attributed to the M8's hydraulic clutch fluid viscosity at low temperatures and typically resolves as the engine warms. Using the correct H-D specification hydraulic fluid minimizes the issue.
Front fender bracket vibration: The 19-inch front wheel and Showa SDBV fork combination can transmit vibration to the front fender brackets, causing a rattle at certain engine RPMs. Checking bracket torque and adding rubber isolators resolves the noise.
Commonly replaced FLHX Street Glide 107ci parts
- Exhaust header gaskets and exhaust system
- Lowered rear air shocks and seals
- Boom! Box head unit (4.3, 6.5GT, or GTS)
- Batwing fairing shell and smoked wind deflector
- 19" Enforcer front wheel
- Saddlebags with One-Touch latches
- Primary chain tensioner shoe
- Front fender and fender brackets
Frequently asked questions
Q: Are 2017-2018 Street Glide parts compatible with the 2019 model?
Most chassis, bodywork, and accessory parts interchange across 2017-2019. The critical exception is the engine: if the 2019 bike is an FLHXS Special with the M8 114, engine internals (cylinders, pistons) differ from the 107. The 2019 Special also uses the Boom! Box GTS head unit with Apple CarPlay, which has different wiring connectors than the 2017-2018 units. Saddlebags, fairing, fenders, wheels, and suspension components are shared across all three years.
Q: Will 2014-2016 TC103 Rushmore Street Glide saddlebags fit my 2017+ M8 model?
Generally yes. The M8 Touring frame carried over the Rushmore chassis dimensions, and the One-Touch saddlebag mounting system from 2014-2016 is compatible with 2017+ models. The bag shape, latch mechanism, and support brackets are shared. Some owners report that 2018+ extended saddlebag lowers from the Special are a popular upgrade that also fits 2014-2016 bikes.
Q: Can I upgrade my M8 107 Street Glide to 114ci or larger?
Yes. The M8 107 and 114 share crankcase architecture. Harley offers Screamin' Eagle Stage kits: Stage III takes the 107 to 114ci (new cylinders and pistons), and Stage IV reaches 128ci or 131ci (new cylinders, pistons, heads, cam, and throttle body). All kits bolt onto the factory M8 107 cases and require an ECM tune. The 107 cases accept all M8 displacement configurations from 107 through 131ci.
Inspected by Powersports Technicians • Only One in Stock • Ships Fast from Florida
